Relationships between maternal immunity to herpes simplex virus and the risk of neonatal herpesvirus infection

Current seroepidemiologic studies performed with assays that measure type-specific antibodies to herpes simplex virus (HSV) type 2 have demonstrated that infection due to the virus is common among women of child-bearing age. With regard to perinatal transmission of HSV, the virus infects nearly 50% of infants whose mothers have primary genital herpes, whereas less than 5% of infants exposed to recurrent maternal infection at the time of delivery become infected. Maternal immunity may also influence the clinical manifestations of neonatal herpes, with primary maternal infection more likely to be associated with disseminated disease in the infant. An effective HSV vaccine could alter the prevalence of neonatal herpes by (1) reducing women's risk of acquiring primary genital herpes during pregnancy and (2) boosting immunity in mothers for whom serologic evidence of previous infection due to HSV type 2 has been noted, which will enhance the transplacental transfer of virus-specific antibodies.